Warning for bad behavior from Riot

So I played a bad round with corki and had to listen to a toxic player the whole time, muted him n such. Than after game he tells the lobby I was toxic and feeding. I get reported by the enemy team and I get a msg from riot saying you've been reported for bad behavior we understand everyone has bad games but improve your behavior or be punished. The Fck.. I said nothing all game and put up with his toxicness only to have riot say I was the one at fault for having bad behavior and to behave or be punished. Let it be known if you play bad and have someone after game say report him for whatever, you can be punished somehow. I literally said nothing except at the end to defend myself by saying I had a bad game and I apologize, my reward for sticking up for myself was a warning from riot. Seeing this system in action has put me to the point of using it against others now. I plan on making similar statements after games against players who don't perform at my level so that they may be punished by riot. Seems fair, punish the weak or anyone having a bad game, reward the trolls and toxic players. I don't like this system but I play to win so ill use whatever tools are at my disposal.

P.S. I was legit hurt from the name calling n such but to have a warning issued by riot was overboard. Hope no one has a similar situation but I would guess it's happing quite often to many players.